I bought the wrong LED's.
The LED's in there take a forward voltage of 3v.
The xbox only gives out 1.5max when running on batterys, so its dim when the play and charge isnt connected.
When the Play&Charge is connected, it ups to 3.2v, so its alot brighter (As seen in pic)
If you buy the standard LED's (1.5v) you need a resistor, so thats more work and more shit trying to fit and close in the controller